Urinary balantidiasis in a patient with systemic lupus erythematosus and lupus nephritis: a case report

BACKGROUND: Balantidium coli, a parasitic unicellular ciliate, often causes asymptomatic balantidiasis of the colon, but extraintestinal disease may occur rarely in immunosuppressed individuals. Renal balantidiasis associated with systemic lupus erythematosus has not been reported before. CASE PRESENTATION: We present a case of a 48-year-old Thai woman who presented with nephrotic syndrome due to systemic lupus erythematosus–related nephritis. Initially, few B. coli cysts were found in urine sediment, but these increased substantially following treatment with prednisolone. She made an uneventful recovery with 10 days of oral tetracycline therapy. No B. coli cysts were found in her stool. CONCLUSION: The route of infection in our patient was unclear but is likely to have been orofecal. Neither her infection nor its treatment caused a deterioration in her renal function.